[ERROR:flutter/lib/ui/ui_dart_state.cc(177)] 未处理的异常：NoSuchMethodError：方法 '[]' 在 null 上被调用。
[ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: NoSuchMethodError: The method '[]' was called on null.
E/flutter ( 8471): Receiver: null
E/flutter ( 8471): Tried calling: []("runnerId")
E/flutter ( 8471): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
E/flutter ( 8471): #1 new Metadata.fromMap (package:jsonfatch/model/event.dart:348:22)
E/flutter ( 8471): #2 new MarketRunner.fromMap (package:jsonfatch/model/event.dart:329:28)
E/flutter ( 8471): #3 new Market.fromMap.<anonymous closure> (package:jsonfatch/model/event.dart:138:52)
E/flutter ( 8471): #4 MappedListIterable.elementAt (dart:_internal/iterable.dart:417:31)
E/flutter ( 8471): #5 ListIterator.moveNext (dart:_internal/iterable.dart:343:26)
E/flutter ( 8471): #6 new List.from (dart:core-patch/array_patch.dart:57:19)
E/flutter ( 8471): #7 new Market.fromMap (package:jsonfatch/model/event.dart:137:18)
E/flutter ( 8471): #8 new EventDetails.fromMap.<anonymous closure> (package:jsonfatch/model/event.dart:65:62)
E/flutter ( 8471): #9 MappedListIterable.elementAt (dart:_internal/iterable.dart:417:31)
E/flutter ( 8471): #10 ListIterator.moveNext (dart:_internal/iterable.dart:343:26)
E/flutter ( 8471): #11 new List.from (dart:core-patch/array_patch.dart:57:19)
E/flutter ( 8471): #12 new EventDetails.fromMap (package:jsonfatch/model/event.dart:65:11)
E/flutter ( 8471): #13 HomePageState.loadData.<anonymous closure> (package:jsonfatch/home.dart:28:51)
E/flutter ( 8471): #14 MappedListIterable.elementAt (dart:_internal/iterable.dart:417:31)
E/flutter ( 8471): #15 ListIterator.moveNext (dart:_internal/iterable.dart:343:26)
E/flutter ( 8471): #16 new List.from (dart:core-patch/array_patch.dart:38:29)
E/flutter ( 8471): #17 new List.of (dart:core-patch/array_patch.dart:68:17)
E/flutter ( 8471): #18 ListIterable.toList (dart:_internal/iterable.dart:211:44)
E/flutter ( 8471): #19 HomePageState.loadData (package:jsonfatch/home.dart:29:10)
E/flutter ( 8471): <asynchronous suspension>
E/flutter ( 8471): #20 HomePageState.initState (package:jsonfatch/home.dart:19:5)
E/flutter ( 8471): #21 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4765:58)
E/flutter ( 8471): #22 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter ( 8471): #23 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter ( 8471): #24 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter ( 8471): #25 RenderObjectToWidgetElement._rebuild (package:flutter/src/widgets/binding.dart:1252:16)
E/flutter ( 8471): #26 RenderObjectToWidgetElement.mount (package:flutter/src/widgets/binding.dart:1223:5)E/flutter ( 8471): #27 RenderObjectToWidgetAdapter.attachToRenderTree.<anonymous closure> (package:flutter/src/widgets/binding.dart:1165:17)
E/flutter ( 8471): #28 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2683:19)
E/flutter ( 8471): #29 RenderObjectToWidgetAdapter.attachToRenderTree (package:flutter/src/widgets/binding.dart:1164:13)
E/flutter ( 8471): #30 WidgetsBinding.attachRootWidget (package:flutter/src/widgets/binding.dart:974:7)
E/flutter ( 8471): #31 WidgetsBinding.scheduleAttachRootWidget.<anonymous closure> (package:flutter/src/widgets/binding.dart:955:7)
E/flutter ( 8471): #32 _rootRun (dart:async/zone.dart:1182:47)
E/flutter ( 8471): #33 _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter ( 8471): #34 _CustomZone.runGuarded (dart:async/zone.dart:997:7)
E/flutter ( 8471): #35 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1037:23)
E/flutter ( 8471): #36 _rootRun (dart:async/zone.dart:1190:13)
E/flutter ( 8471): #37 _CustomZone.run (dart:async/zone.dart:1093:19)
E/flutter ( 8471): #38 _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:1021:23)
E/flutter ( 8471): #39 Timer._createTimer.<anonymous closure> (dart:async-patch/timer_patch.dart:18:15)
E/flutter ( 8471): #40 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:397:19)
E/flutter ( 8471): #41 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:428:5)
E/flutter ( 8471): #42 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
我的 json 文件，其中的数据是嵌套的 key value per and do many json obj
"runners":[
{
"id":10301,
"name":"roman",
"sortPriority":0,
"metadata":{
"runnerId":"10301"
}
},
{
"id":7337,
"name":"khali",
"sortPriority":0,
"metadata":{
"runnerId":"7337"
}
}
],
我的 runnerId 地图代码。它是一个嵌套的数组对象。其他所有我在模型文件中映射的
class Metadata {
Metadata({
this.runnerId,
});
String runnerId;
factory Metadata.fromMap(Map<String, dynamic> map) => Metadata(
runnerId: map["runnerId"],
);
Map<String, dynamic> toMap() => {
"runnerId": runnerId,
};
}
我的家.dart 代码
class HomePage extends StatefulWidget {
@override
HomePageState createState() => HomePageState();
}
class HomePageState extends State<HomePage> {
@override
void initState() {
super.initState();
loadData();
}
loadData() async {
await Future.delayed(Duration(seconds: 2));
var cktJson = await rootBundle.loadString("assets/files/ckt.json");
var decodedData = jsonDecode(cktJson);
var cricketData = decodedData["cktdata"];
EventsModel.markets = List.from(cricketData)
.map<EventDetails>((item) => EventDetails.fromMap(item))
.toList();
setState(() {});
print("Decoded :-"+decodedData);
print("CrircktD :-"+ cricketData);
}
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: Scaffold(
appBar: AppBar(
backgroundColor: MainBackgroundColor,
title: Text("Radhe Json Fatch"),
),
body: SafeArea(
child: Column(
children: [
Expanded(
child: (EventsModel.markets != null && EventsModel.markets.isNotEmpty)?
ListView.builder(
scrollDirection: Axis.vertical,
itemCount: EventsModel.markets.length,
itemBuilder: (context, index) {
return LiveEventCricket(item: EventsModel.markets[index]);
},
):Center(child: CircularProgressIndicator()),
),
],
),
),
),
);
}
}